1. Field of the Invention
Exemplary embodiments in accordance with principles of inventive concepts relate to a semiconductor device and a method for fabricating the same.
2. Description of the Related Art
As the feature size of an MOS transistor decreases, the length of a gate and a length of a channel formed under the gate also decrease. As the thickness of a silicon oxide film typically used as a gate insulation film shrinks, the electrical properties of the film may be negatively affected. As a result, high-k dielectric films, having high dielectric constants, may be used in place of conventional silicon oxide films. A high-k dielectric film can reduce leakage current between a gate electrode and a channel region while maintaining a small equivalent oxide thickness. Additionally, the polysilicon typically used as a gate material has larger resistance than most metals and, therefore, a polysilicon gate electrode may be replaced by a metal gate electrode.